Physical activation of El Cerrejón coal was performed to evaluate different activation conditions and obtain active carbons with different properties. These ctivated carbons were characterized using the iodine and methylene blue indexes (ASTM D 4607, NTC 4467). We found that the activated carbon obtained by physical activation was able to remove up to 70% of dyes and that it had a good potential to be used in the treatment of industrial waters contaminated with dyes from the textile industry. © Acad. Colomb. Cienc. Ex. Fis. Nat. 2015.